Apparatus and process for continuous determination of percentage boiling point



H. NEIL APPARATUS AND PROCESS FOR CONTINUOUS DETERMINATION May 31, 1966 R OF PERCENTAGE BOILING POINT 4 Sheets-Sheet 1 Filed Aug. 17, 1962 INVENTOR. 205.5544 H N94 May 31, 1966 R. H. NEIL 3,253,454

APPARATUS AND PROCESS FOR CONTINUOUS DETERMINATION OF PERCENTAGE BOILING POINT 4 Sheets-Sheet 2 Filed Aug. 17, 1962 Mum 3:

INVENTOR. 24/5554 A. N54

MM Q5 W, M W 477084/575 May 31, 1966 Filed Aug. 1'7, 1962 R. H. NEIL 3,253,454

APPARATUS AND PROCESS FOR CONTINUOUS DETERMINATION OF PERCENTAGE BOILING POINT 4 SheetsSheet 5 310 I i i .916 \314 724M" x301 D0652 INVENTOR. 05554; H N's/.4

g MW May 31, 1966 R. H. NEIL 3,253,454

APPARATUS AND PROCESS FOR CONTINUOUS DETERMINATION OF PERCENTAGE BOILING POINT Filed Aug. 17, 1962 4 Sheets-Sheet 4 350 sou e/w' p-s 34o --cuevszz 35o evel/[J 290 280 NAP/v 77/4 cue mzzz a /0 2a 5a 4a 5a 0 70 60 90 mo 54MPA fl/ST/ALED INVENTOR. 24/55: H f/L BY 4% MW,

224, Amd% ATTOINAWJ' United States Patent APPARATUS AND PROCESS FOR CONTINUOUS ilEbETERMINATION 0F PERCENTAGE BOILING INT Russell H. Neil, Pasadena, Calif., assignor to Technical 0i] Tool Corporation, Los Angeles, Calif., a corporation of California Filed Aug. 17, 1962, Ser. No. 217,666 32 Claims. (Cl. 73-'17) This application is a continuation-in-part of Serial No.

778,389, entitled Initial Boiling Point Analyzer, filed December 5, 1958, inventor Russell H. Neil, and of Serial No. 831,827, entitled Process and Apparatus for Continuously Determining End Point, filed August 14, 1959, inventor Russell H. Neil, which in turn is a continuationin-part of the application Serial No. 760,941, entitled Distillation End Point Monitor, filed September 15, 1958, inventor Russell H. Neil, now abandoned.

The present invention relates to apparatus for determining and manifesting the percentage boiling point of a fluid. More particularly, it releates to apparatus for determining and manifesting boiling points of a fluid at or close to its initial (zero percent) boiling point, at or close to its end (one hundred percent) boiling point, or at any point therebetween, such as the fifty percent boiling point.

In present industrial practice, continuous measurement of initial, intermediate and end boiling points of a fluid, such as gasoline or naphtha, are extremely important as an indication of chemical or physical properties of the fluid being produced. Thus, a 10% boiling point test (which comprises determining the temperature of a boil: ing sample of the fluid being tested when 10% has been distilled off) is called for, in many instances, in the manufacturing of petroleum. A 20%, 40%, 60% or 80% boiling point test may also be called for in other chemical manufacturing operations, and in distillation of other products.

The continuous determination of a particular percentage boiling point is of great importance, to cite just one example, in the blending of gasoline. A heavy gasoline fraction should not have any portion thereof of end point (e.g., the 90% or 95% point) above a certain boiling point because of the possibility of accumulation of residues in engines. The initial point (e.g., the 5% or point) of a light fraction should not be below a certain specified point because of the possibility of vaporization in the fuel lines. The 50% point is also used as a measure of the quality of final blend of gasoline. Close control of these variables is essential. The use of analyzers which operate on essentially the same principle over the entire range of percentage boiling points would be extremely desirable since maintenance of such equipment would be simplified, and ease of operation by lay operators would be enhanced.

The initial or end boiling points of a fluid may be determined rather simply and'easily in the laboratory by heating the fluid uniformly and observing the temperature at which boiling initially or ultimately occurs. However, the laboratory method of determining the initial-or end boiling point temperature requires some time lapse and must be closely attended. Therefore, if these methods are employed to obtain measurements to be used for guides in production, the time required to obtain the initial or end point may result in a substantial variation from the desired product before corrections are made. Therefore, a need exists for a reliable apparatus to receive a sample stream of fluid-and relatively continuously indicate the initial or end boiling point of the received sample. A great need also exists for the same apparatus to measure percentage boiling points from the zero initial boiling point all the way to the 50% boiling point, and for that apparatus to measure percentage boiling point of from 51% to the boiling point, with little structural modification.

With the foregoing in mind, it is a major object of the present invention to provide an improved apparatus for continuously determining the percentage boiling point of a fluid from its zero initial point to approximately its 50% boiling point.

Another major object of the invention is to provide an improved apparatus adapted to receive a sample stream of fluid substance, and continually manifest the percentage boiling point of the received substance from approximately the 51% boiling point to approximately the 100% boiling point.

It is also an object of the invention to provide an instrument which may be economically constructed for continuously and accurately manifesting the various percentage boiling points of a received stream of sample fluid.

A further object of-the present invention is to provide an apparatus for manifesting the various percentage boiling points of a sample fluid which system does not require complex heat-transfer apparatus.

Still a further object of the present invention is to provide a device of the character described for manifesting all of the various percentage boiling points of a fluid, which apparatus is relatively simple to manufacture and maintain.

Another object of the present invention-is to provide an apparatus wherein a stream of sample fluid is accumulated in a pool which is maintained at the initial boiling point of the fluid in the pool, and from which liquid and vapor are removed under positive control of the apparatus.

Still another object of the present invention is to provide an improved process and apparatus for continuously measuring the temperature of a predetermined minor proportion of a fluid sample, and comprising the heaviest components thereof, to thereby continuously measure the end point of said fluid sample.

These and other objects and advantages of the present invention will become apparent from the following detailed description of two preferred embodiments thereof and from an' inspection of the accompanying drawings in which:

FIGURE 1 is a diagrammatic representation of an apparatus constructed in accordance with the present invention specifically adapted for measurement of percentage boiling points from about the 0% boiling point to about the 50% boiling point;

FIGURE 2 is a diagrammatic representation of an apparatus constructed in accordance with the present invention and specifically adapted for measurement of percentage boiling points from about 50% to near 100%;

FIGURE 3 is a diagrammatic representation of modified apparatus constructed in accordance with the present invention and specifically adapted for measurement of percentage boiling points ranging from about 50% to near 100%; and 7 FIGURE 4 shows typical boiling temperatures for various petroleum products.

In general, the apparatus and process of the present invention functions to develop a pool P, comprising the heaviest components of the stream under observation. The pool P may also contain the lightest or intermediate temperatured components of the stream, depending upon the range of percentage point to be measured. The pool P is maintained at a temperature to vaporize the liquid of the pool, which temperature is sensed and manifested by a thermometer or other temperature sensing means. The specific percentage of boiling point to be measured is selected by means of regulation of the ratio of vapor discharge to liquid discharge from the pool P.

The vapor discharge, for example, for a 40% boiling point, is regulated so that approximately 40% of the feed is discharged through the vapor orifice. The measurement of the exact 40% boiling point is then readily obtained by simple calibration of the equipment. Once the proper vapor-to-liquid outlet ratio is established for the particular percentage boiling point to be measured, that percentage boiling point is automatically maintained due to control means including valve means in the discharge lines which are openable and closable in accordance with the vapor pressure developed by the vapor. As a predetermined vapor pressure is reached (an operating system pressure of slightly above atmospheric up to 25 p.s.i.g. is presently used, although a pressure below atmospheric, e.g., as low as mm. Hg pressure is preferred in some operations), vapor discharge and liquid discharge com mence in the same predetermined proportion. As the pressure decreases, due to vapor discharge, below the predetermined pressure, both liquid and vapor discharge cease. The additional feed introduced to maintain a predetermined level boils and the 40% boiling point temperature continues to be measured in the pool P as the vapor and liquid discharges in predetermined proportion through their respective outlets in response to the vapor pressure developed.

The percentage of boiling point actually measured is accurate for the pressure at which the system is operating. The percentage boiling point at atmospheric pressure is readily determined by simple calculation.

The system generally described may be used either as an initial boiling point (IBP) system or as end boiling point (EBP) system. To employ the system for IBP purposes, the vapor discharge line is restricted by various sized orifices, depending on the-percentage boiling point to be measured, and the bottoms discharge line is completely open or unrestricted. Condensation of the outlet vapor is not usually required. The sample introduced into the boiling pot is not previously distilled so that it contains all components including the zero percent boiling point component up to the 100% boiling point component.

The EBP system employs a distillation tower through which the incoming sample is first fractionated so that material containing primarily heavy components (51% to 100%) is introduced to the pool P. The vapor discharge line is unrestricted and the liquid discharge from the pool P is provided with one of a number of orifices which effectively restrict the discharge opening and varies the ratio of liquid-to-vapor discharge so that the vapor discharge is predetermined and lies within approximately 51% to 100% by volume (condensed) of the volume of the feed. Since there is substantial vapor discharged, a condenser for the vapor discharge is generally employed.

The operation of two preferred apparatuses and processes for measuring from the 050% boiling point and from the 51%-100% boiling point will now be described. This is not to imply that the instruments cannot be used above the 50% or below the 50% point, respectively, but operation within these ranges is preferred. For purposes of this specification and claims, the term initial boiling point (or IBP) will be defined as any percentage boiling point between 050%, and the term end boiling point (or EBP) will be defined as any percentage boiling point between 51-100%.

Referring now to FIGURE 1, in general, the apparatus to measure the IBP receives sample fluid which is accumulated in a pool P that is maintained essentially constant in volume by regulating the flow into the pool. The fluid enters the pool P at a temperature below the initial boiling point, and the pool is heated to the initial boiling point to release vapors which develop a positive pressure. The pressure is maintained essentially constant by controlling the discharge of liquid and vapor from the confines of the pool P. Fresh fluid, the flow of which depends upon the amount of vapor produced from the pool P is introduced into the pool. The pool is maintained at its initial boiling point due to the control of pressure and vapor-liquid discharge. The initial boiling point temperature of the pool P is manifested by a thermometer or other temperature sensing means. If a different percentage boiling point is to be measured, the ratio of vapor to liquid drawotf from the pool P is readily changed by varying the size ofliquid discharge orifice.

Referring now to FIGURE 1 in greater detail, the fluid pool P is confined in a closed vaporizing chamber 10, which is capable of. withstanding limited internal pressures. Inside the vaporizing chamber 10 is a doublewalled pot structure including a cylindrical external pot or bubble guide 11 which telescopically receives a smaller cylindrical float shield or internal pot 12, so that a space is formed between the pots. The bottoms of the internal and external pots contain apertures 14 and 16, respectively, which are separated by spreader or circular plate 18 mounted above the bottom of the external pot 11 and below the bottom of the internal pot 12. The purpose of the double-walled pot structure is to minimize bubbling and frothing adjacent the float 20, and thereby assure smoother operation of the float.

The float 20, which may comprise a hollow metal cylinder, is telescopically mounted inside the internal pot 12 so as to be freely movable in a vertical direction but capable of only a limited movement in a horizontal direction. A rod 22 is aflixed to the upper surface of the float 20, and extends upwardly to the cover plate 24 of the vaporizing chamber 10 to control an intake valve 26 mounted in the cover plate. The valve 26 is connected through a duct 28 to a cooling unit 30 which is in turn connected to receive a stream of the sample fluid under pressure through a duct 32. The cooling unit 30 is thermostatically controlled to assure that the temperature of the sample fluid is below the initial boiling point thereof. The cooling unit may incorporate a variable thermostatic control system to provide fluid in theduct 28 at any preselected temperature within limits.

An electrical resistance coil 34 is mounted adjacent the bottom of the vaporizing chamber 10 and serves to provide'heat to the pool P. The resistance coil 34 is electrically connected across terminals 36 which are in turn adapted to be connected to a source of electrical power for continuously supplying energy to the coil while the system is in operation.

The thermometer, for sensing the initial boiling point temperature, includes a tube 38, housing a temperatureresponsive element (not shown). The tube is mounted in the cover plate 24 to extend from within the pool P out of the vaporizing chamber 10 and connect with a dial 40 for manifesting the temperature. The thermometer T may comprise a thermocouple apparatus, pneumatic transmitter, or other means, as well known in the prior art. The temperature sensing means can include apparatus producing an analog electrical signal. Of course, in the event that the analysis performed by the system as shown in FIGURE 1 is to be employed to control production, the electrical signal manifesting the initial boiling point will normally be utilized at a point remote from the analyzer.

Fluid is discharged from the vaporizing chamber 10 through a duct 42, that passes through the cover plate 24 and extends inside the chamber 10 to a location near the bottom of the pot 11. The duct 42 is open at the end 44 adjacent the pot 11, to permit fluid to be discharged from the pool P. Vapor from the pot 11 is discharged through a duct 45, which has an orifice 46 of specific size provided therein. The duct 45 has its inlet well i above the surface of the pool P.

which T joint is provided with a ball-check valve 470. The outlet from the T joint is connected with the outlet duct 42a. The ball-check arrangement prevents any siphon break in duct '42 by means of the vapor in duct 45, yet allows vapors to be discharged through orifice 46 in a predetermined proportion to liquid, this proportion being determined by the size of the orifice 46. The ball check valve 470, more specifically, enables the duct 42 to be filled with liquid even between cycles of liquid discharging through duct 42. Thus, for example, if dis charge through duct 42 momentarily ceases ball-check valve 47a immediately seats at the outlet of duct 42, creating a partial vacuum, and the vapor pressure Within the chamber is usually sufficient to maintain liquid in duct 42. The valve 47a is not a float valve, its function being basically to open or close the outlet end of duct 42.

The duct 42 extends out of the vaporizing chamber to a pneumatic-control system 48, which has a pressuresensing connection to the interior of the vaporizing chamber 10 in the form of a duct 50 that passes through the cover plate 24. The duct 50 applies the pressure in the vaporizing chamber 10 to the pneumatic control system 48 to control the discharge of liquid and vapor, i.e., gas, through the duct 4221.

The pneumatic control system 48 incorporates pneumatic amplifiers 52 and 54, which intensity or amplify pressure signals in the duct 50 and control a pneumatic valve 56 in accordance therewith. The amplifier 52 comprises a circular diaphragm 60 mounted within a cylindrical chamber 62 which diaphragm functions to control a valve 64 in a passage 66 including the lower part of the chamber 62, an outlet 65 and an intake 67, which contains a flow-limiting orifice 68. The intake 67 of the passage 66 is adapted to be connected to a source of compressed air.

The passage 66 extends to the second pneumatic amplifier 54, which is similar to the amplifier 52 and includes a circular diaphragm 70, mounted in a cylindrical chamber 72 to control a valve 74. The valve 74 is placed in a passage 76, which includes the lower part of the chamber 72, an outlet 73, and an intake 75, which is obstructed by an orifice 78. The intake 75 is also adapted to be connected to a source of compressed air.

The passage '76 is connected to the pneumatic valve 56 which includes a circular diaphragm 80 mounted in a cylindrical chamber 81 to be variously distorted to control the position of a spring-mounted ball valve 134 that is positioned between the duct 42a and a discharge duct 84. The diaphragm 80 is connected to a rod 86, which extends through a bore 88, to engage a ball 90. The ball is seated on a coil spring )2 so that the ball 90 is urged upwardly to close the bore 88. The ball 99 and the spring 92 are housed in a chamber 24 connected to the duct 42a.

Prior to operating the system as shown in FIGURE 1 to analyze the initial boiling point of any particular range of fluids, the control system of the cooling unit 30 is adjusted. The cooling unit 30 is set to assure that fluid entering the duct 28 is at a temperature below the initial boiling point of the sample fluid. Of course, in many instances, the fluid as received by the apparatus through the duct'32 is already at a temperature well below the initial boiling point and the cooling unit 369 does not operate.

Fluid emerging from the cooling unit 30 passes through the duct 28 and the valve 26 to enter the vaporizing chamber 10. The float 20 maintains the valve 26 open until a pool of some predetermined volume is accumulated in the vaporizing chamber. The pool P is then heated by the resistance coil 34 to the initial boiling point of the fluid in the pool. At the initial boiling point of the fluid in the pool P, vapor is formed which develops a positive pressure that is applied to the pneumatic control system 48 through the duct 50. The pneumatic control system 48 functions to open the valve 82 to allow 6 liquid and vapor, or gas, to pass through the duct 42a and be discharged through the outlet 84.

The size of the orifice 46 is chosen so that, if the initial boiling point to be measured is the 10% point, the amount of gas passing off through the orifice is close to 10% of the total liquid and vapor discharge. By comparison of the 10% point measured by the apparatus with a calibrated curve of a 10% boiling point, the instrument can be calibrated to measure the exact 10% point. It is to be noted that the gas discharged through the orifice 46 in the T joint 47 includes air contained in the fluid sample as well as vapor formed from the pool P. That is, air is normally driven from a fluid upon heating. Therefore, when the fluid in 'the pool P is heated, air driven therefrom must first be removed to enable the system to function properly.

With the discharge of fluid from the vaporizing chamber 10 through the duct 42., the liquid level of the pool P drops and fresh sample fluid enters the vaporizing chamber 19 through the duct 28 and the valve 26. The entry of fresh fluid into the vaporizing chamber it) cools the pool P. Consequently, the rate at which vapor is produced from the pool P determines the rate at which fluid is discharged from the chamber 10 and the rate at which cool fluid enters the chamber. Therefore, for any particular sample fluid, the pool P will reach an equilib rium temperature which is the preset initial boiling point.

If lighter fractions, having lower initial boiling point, are introduced into the chamber 10, vapor production is increased to result in an increased rate of flow through the chamber, to reduce the temperature of the pool P. Conversely, if the fluid sample changes to a fluid with a higher initial boiling point, the vapor production rate decreases, to reduce the rate of flow through the chamber 10 and allow the temperature to rise. Therefore, the temperature of the pool stabilizes at the preset initial boiling point of the received sample which is manifested by the thermometer.

As fluid enters and leaves the vaporizing chamber 10 and the pool P boils, fluid moves around the internal and external pots 11 and 12 and the plate 18. This movement of the fluid in the pool P effectively stirs the fluid, thereby tending to maintain the pool P at a substantially uniform temperature. As a result, the amount of fluid in a critical state is minimized, and operation is stabilized.

Considering the operation of the pneumatic control system 48 to discharge fluid in acordance with the pressure in the chamber 10, as the pressure in the duct 50 increases, the diaphragm 60 is distorted downwardly, closing the valve 64 and restricting the flow of air through the passage 66. Consequently, the presssure in the passage 66 sharply increases to distort the diaphragm 79, in the amplifier 54, downwardly to constrict the passage 76 and cause an even sharper pressure increase therein. The :pressure in the passage 76 controls the diaphragm and as the pressure in the passage 76 increases the diaphragm 89 is deformed downwardly to compress the spring 92 and urge the ball 90 out of the bore 88 to open the valve 82.

It may, therefore, be seen that the pneumatic control system 48 is very responsive to the pressure in the vaporizing chamber 10 and functions to promptly discharge gas and liquid from the vaporizing chamber at a predetermined pressure.

An important feature of the IBP analyzer embodied in the present invention resides in the use of a control system to remove fluid in the form of gas and liquid from the vaporizing chamber 10 in a controlled fashion according to the pressure therein. Another important feature of the IBP analyzer resides in the fact that heat is supplied in the system at a constant rate and exacting heat control apparatus is not required. Still another feature of the IBP analyzer invention resides in the pots 11 and 12 and the plate 18 which comprise a bubble guide and spreader structure to minimize the volume of liquid in the critical state.

Attention is also drawn to the fact that the IBP to be measured can be readily reset to any desired percentage point between about zero to about 50 percent by employing an orifice 46 of a size such that the percentage of vapor, by volume, of the total liquid and vapor discharge passing through the orifice 46 is approximately equal to the perecntage boiling point desired to be measured.

From the foregoing, it will be apparent to those skilled in the art of the present invention to provide a greatly improved and satisfactory initial boiling point analyzer, capable of achieving the objects and advantages herein set forth.

Turning now to the EBP apparatus, the EBP apparatus and EBP process functions to develop a pool P comprising the heaviest component of a stream of the volatile fluid under observation. The pool P is maintained at a temperature to vaporize the liquid of the pool, which temperature is sensed and manifested by a thermometer. It may be seen, therefore, that the temperature sensed by the thermometer is the vaporization temperature of the heaviest component of the sample stream, which is the end point temperature.

The maintenance of a preset (and continuous) end point measurment of between 51% and 100% is obtained, as with the IBP apparatus, by maintaining a preset proportion of vapor discharge to liquid discharge from the pool P. In obtaining an end point measurement, however, the vapor discharge is substantially greater than the liquid discharge, and the liquid discharge pipe is generally restricted with an orifice of a size such that the ratio of vapor discharge to total vapor and liquid discharge is approximately equal to the percentage point desired to be continuously measured. Thus, if a 60% end point is to be continuously measured, the liquid discharge orifice chosen is of a size such that only approximately 40% of the total liquid and vapor discharge passes through the liquid discharge orifice.

Referring now to FIGURE 2 in greater detail, the fluid pool P is confined in a vaporizing chamber 110 which is, preferably, integrally formed with a fractionating tower 112. The fractionating tower 112 contains a larger number of small non-mating elements 112a, which may be ceramic material and may take the form of ele ments termed saddles in the distillation art. The elements in the fractionating tower serve to provide considerable surface area, which facilitates the separation of the fluid in the tower into components. As a result, fluid introduced at the top of the heated tower is separated into components in a manner well known in the prior art, so that only the heavy components reach the bottom of the fractionating column 112.

The non-mating elements, e.g., saddles, are supported in the fractionating-tower 112 by a screen 113 which is positioned between the tower and the vaporizing chamber 110. Thus, fluid can pass between the tower and the chamber.

The vaporizing chamber 110 contains a float 114 which is mounted in a double pot including inner pot 115 and outer pot 116, to permit vertical movement of the float while preventing horizontal displacement. The double pot also acts as a bubble control and serves to control the pool P. The pots 115 and 116 have apertures in their bottoms which are separated by a plate 117. The float 114 is mechanically coupled to a valve 118 by a rod 120, which rod passes through the fractionating tower 112. The vaporizing chamber also contains a thermometer having a thermometer bulb 121 for sensing the temperature in the chamber. The thermometer is connected to control a temperature-manifesting gauge 123.

A liquid outlet 122 from the chamber 110 receives a duct 124 which divides into lines 126 and 128. The line 128 is connected through a manually operated valve 130 to a disposal duct 132 that may, in turn, be connected to a waste dump. The line 126 is connected through a solenoid-controlled valve 135 and a drain-proportioning orifice 136 to the disposal duct 132. The solenoid coil employed to control the solenoid-operated valve 135 will be considered hereinafter. A pressure gauge 138 may be employed in the disposal duct 132 to indicate the pressure therein.

An electrical heating element 140 is positioned adjacent to the vaporizing chamber 110 to supply heat to the pool P. The heating element 140 may simply comprise a resistance heater, which is connected to be energized through contacts 144 from a source of electrical potential that may be connected to terminals 142. Heat is supplied to said pool P, at preferably a constant rate, and the heat supply is suflicient to keep said pool P at its boiling point, when equilibrium is reached in the vaporizing ohamber.

The intake valve 118, located in the upper portion of the fractionating tower 112, is connected to an intake duct 145 through which the stream of sample fluid is received to be tested. A pressure gauge 146 indicates the pressure in the duct 145 and a pressure-responsive bellows 148, also connected to the duct 145, is mechanically coupled to control the contacts 144 so that the contacts 144 are open when the pressure in the line 145 drops below a predetermined level.

A vapor outlet 150, located at the upper end of the fractionating tower 112, is connected to a duct 152. The pressure in the duct 152 is indicated by a pressure gauge 154, and a pressure-responsive bellows 156 is connected to the duct 152 and functions to control electrical contacts 158. The contacts 158 are serially connected with parallel-connected relay coils 160 and 162, to form a circuit that is connected across terminals 164, which are adapted to be connected to a source of power. The solenoid 162 functions to control the solenoid-operated valve 135 in the line 126 and the solenoid 160 controls a solenoid-operated valve 166 between the duct 152 and a duct 167 that is connected to the disposal duct 132. A duct 168, connected around the solenoid-operated valve 166, contains a pressure-limiting relief valve 170 which opens in the event that the pressure in the duct 152 (and the tower 112) rises above a desired pressure. The sensitivity of the pressure control apparatus is such as to hold the pressure essentially constant while permitting a variable flow rate of the sample.

The end point monitor apparatus is placed in operation by closing the manually operated drain valve 130 and connecting the terminals 142 and 164 to a suitable source of electrical energy. The intake duct 145 is then sulpplied with a liquid sample of the fluid to be tested. As the vaporizing chamber 110 is empty, the float 114 is in a low position, causing the valve 118 to be open. As a result, the liquid sample flows into the vaporizing chamber 110 through the fractionating tower 112. As the liquid level rises in the fractionating tower 112, the float 114 rises and closes the valve 118 to prevent the entry of further liquid into the fractionating tower 112. As the pressure in the line 145 rises, the pressure-responsive bellows 148 expands to close the contacts 144. Closure ofthe contacts 144 provides electrical energy to the heating element 140, causing the element to heat the vaporizing chamber 110. As the pool P in the vaporizing chamber 110 is heated, the lighter components of the liquid are vaporized to develop pressure in the fractionating tower 112. Upon reaching a predetermined value, the pressure in the tower expands the pressure-responsive bellows 156 to close the contacts 158. Closure of the contacts 158 energizes the solenoid coils 160 and 162, thereby opening the valves 135 and 166 to discharge vapor and liquid from the apparatus. With the opening of the valve 166, the pressure in the duct 152 is relieved, thereby causing the pressure-responsive bellows 156 to openthe contacts 158 and de-energize the solenoid coils 160 and 162. Of course, with the de-energization of the coil 160, the valve 166 is also closed.

When the coil 162 is energized, the solenoid-operated valve 135 in the line 126 allows a quantity of liquid from the pool P to discharge through the lines 124 and 126, and through the drain-proportioning orifices 136 into the disposal duct 132. Since both the valves 166 and 135 open and close at the same time, the relative amounts of vapor and liquid passed from the chamber 110 bear a fixed ratio to one another. The ratio depends upon the size of orifice 136 (which can readily be varied) or on the size of the opening of valve 166. The amount of liquid permitted to pass from the pool P is thus prolportional ly related to the amount of vapor which passes through the discharge duct 152. T he proportion of liquid discharge to the total liquid and vapor discharge is set at approximately the end point desired to be measured. The instrument is calibrated by comparing its operation with a sample of known end point, so that the exact end point can be read.

Following the operations of my apparatus through from start-up, the pool P is first heated to boiling, under essentially constant pressure, by heater 140 and, as the vapor pressure builds up beyond the pressure required to operate bellows 156, the vapors are removed, via duct 152, while liquid is simultaneously removed, via pipe 124, in intermittent fashion, as described previously. In heating the pool P to boiling, the tower 112 will attain a temperature somewhat less than the pool P temperature, due primarily to vaporization of incoming liquid sample, and, to a lesser degree, heat losses in the tower.

After having set the ratio of pool outflow to vapor outflow in the system by means of the valving system previously described, and after having established a steady state temperature in the chamber 110, additional liquid sample inflow having the same, or substantially the same end point will be vaporized in the present ratio, and only that liquid will enter the pool P which represents the predetermined percentage of the heaviest components of the sample, This phenomenon is a result of the temper-ature equilibrium established in the tower 112. For example, if the preset ratio is 95% vapor outflow to liquid outflow, the sample entering pool P is at equilibrium only 5% of the total incoming sample, the remaining 95 (the lightest components) being vaporized in the tower 112.

Referring to FIGURE 4, and especially to curve I thereof, a typical boiling curve is shown for a petroleum fraction. The curve is a plot of T F.) vs. percent of sample distilled. It will be noted that for fairly accurate measurement of end point, the measurement is generally taken at the 70% point of distillation at least, and preferably 85% or higher. Also, it is desirable, in some instances, to have information regarding other points other than the end point, e.g., the 60% point, in which case the measurement is taken along the 60% point of distillation.

At equilibrium, and with a sample material having a substantially constant end point, the liquid entering the pool P is almost at boiling, and as liquid is discharged from pool P, thenewly admitted sample (the heaviest 5%, in my example) is rapidly brought to a boil by means of the heat input 140, the pool temperature be ing recorded by thermometer. The liquid is then very quickly discharged, enabling more liquid sample to enter via valve 118.

It will thus be seen that very little delay is required before the end point of the new sample is recorded, this end point being essentially the 95% end point in the specific example used, the end point being designated by the letter A on curve I. The specific end point to be measured can be readily varied by selecting the desired ratio and providing an appropriately sized orifice 136, e.g., it may sometimes be as low as 51% vapor drawoff to 49% liquid drawoff. At the other extreme, the

10 end point desired to be measured may be 98-99%, in which case the vapor-liquid drawoff ratio and orifice 136 is changed appropriately. The rate of response of the temperature to end point is faster in the former case.

In short, the rate-proportionating means of my invention determines What percentage of liquid enters the pool P (which percentage can be made variable by different settings of orifice 136), and thus determines, at equilibrium, precisely what end point is being measured or recorded.

Assume now, for example, that the liquid sample in the duct 145 changes to a fluid having a reduced end point. 'Upon such an occurrence, the flow of vapor out of the fractionating tower 112 through the discharge i150 increases as the fluid is subjected to the equilibrium temperature established for the prior fluid. The increased fluid discharge through the line 152 is accompanied by an increased discharge of liquid through the duct 124 because of the interconnected discharge control for the liquid and vapor ducts. As a result of the increase in fluid discharge from the vaporizing chamber and the fractionating tower 112, the liquid flow into the fractionating tower 112 through the valve 118 is increased so that an increased amount of the cooler sample fiuid enters the fractionating tower 112, cooling the fractionating tower and the vaporizing chamber. As the mass rate of sample increases, the temperature, both in the pool P and in the tower 112, is decreased because the throughput of both vapor and liquid through the sampling apparatus 110 is increased while the pressure in the system remains constant.

The rate of cooling of the pool P and the tower 112 occurs on an exponential basis until equilibrium is again reached at a lower temperature corresponding to the particular end point (e.g., 95%) desired to be measured or recorded.

The temperature of the pool P and the tower 112 drops roughly in accordance with the changing end point of the changing sample in the pool P, the pool being comprised in the transient state of fresh and old bottoms. There may be momentary fluctuations but, in the main, the changing end point manifested decreases with decreasing end point of the composite bottoms in pool P.

As the pool P is formed of wholly new bottoms, these bottoms will comprise, at equilibrium, a preset pro-portion of incoming fluid sample to the chamber 110, the present proportion depending on the size of the orifice 136 and the interconnected vapor valving system. That is to say, at equilibrium, the heaviest components (e.g., primarily the heaviest 5%, if the setting of vapor to liquid drawoff is 95:5) reach the pool P since the tower 112 has, at this time, a temperature such that vaporization of all but the heaviest components will occur therein.

Referring to FIGURE 4, curve II, an end point curve of a naphtha petroleum fraction is shown having a 95% end point, designated by the letterB, which is considerably reduced relative to the 95% end point of curve I. If the naphtha, having the boiling point of curve II, were in the sample stream in line and followed the fraction having the boiling point of curve I, and the apparatus were preset to measure the 95 end point, the temperature recorded would'fall from about 305 F., roughly in accordance with the changing end point of the pool P. Soon after the pool P comprises the naphtha fraction only, equilibrium is reached at the lower temperature, and since only the heaviest 5% of the naphtha will reach the pool P, the temperature of boiling at equilibrium of the pool P is approximately 275 F., designated by the letter B.

Considering now an increase in end point of incoming sample from, for example, a sample having the boiling point curve of curve II, to that of curve III, the following steps occur:

As the higher end point material enters tower 112, substantially less vaporization takes place because the in- 11 coming material is subjected only to the relatively low equilibrium temperature established for the prior fluid. Since vaporization decreases, liquid outflow will decrease, the liquid inflow will decrease, or even be shut off.

The temperature of the liquid in pool P will then rise as heat from heater 140 is imparted to the pool, and as temperature rises, vaporization commences, liquid is discharged, and fresh liquid is brought into chamber 110. This process is repeated, and the temperature of the tower 112 and pool P is raised roughly in accordance with the increasing end point of the composite fresh and old bottoms, although momentary fluctuations may take place in this transient period.

As the pool P attains a composition of solvent bottoms only, and upon attainment of steady state, the temperature, at boiling, in pool P is the 95% end point of the solvent (point C on curve III) if the ratio is appropriately adjusted. That is to say, at equilibrium, 95% of the incoming sample is discharged as vapor through valve 166, and as liquid through orifice 136. Thus, at equilibrium, only the heaviest of the naphtha components reach the pool P, the tower temperature being sufficiently high to cause vaporization of all but 5% of the incoming sample.

The rate of response of the apparatus to changes in end point approaches that of an exponential function. Thus, as the end point decreases from T to T the rate of change of temperature is much greater initially than when it approaches close to T Such a phenomenon is highly advantageous inasmuch as industrial practice requires an initially rapid response to change in end point.

The pressure gauge 138 indicates the pressure in the disposal duct 132 and, of course, during normal operations this pressure should be quite low. The pressure gauge 154 indicates the pressure in the tower and serves to indicate that the unit is functioning properly when the pressure reaches a predetermined level. Of course, in the event of a malfunction by the pressure-responsive bellows 156 causing the pressure in the fractionating tower 112 to exceed a safe operating level, the pressure-limiting valve 170 opens to relieve the pressure in the tower.

The pressure gauge 146, manifesting the pressure of the liquid sample in the line 145, effectively indicates the presence of the liquid sample. If the source of the liquid sample stream to the line 145 becomes blocked, the pressure in the line 145 drops, thereby allowing the pressureresponsive bellows 148 to contact and open the contacts 144. As a result, in the absence of sample fluid, the vaporizing chamber 110 is prevented from boiling dry and thereby being heated to excessive temperatures.

Attention is drawn to the fact that the vapor-liquid interconnected drawoff and the preset vapor-liquid ratio are important parts of the functioning of my apparatus and process, both in the EBP and IBP measurement. If there were no dependence between the vapor and liquid drawoff, there would be no assurance that one line would dicharge when the other did, and the result would be a fluctuating and nonreliable percentage boiling point that would be a measure of only some indeterminable point along the boiling point curve from 0 to 100%.

Attention is also drawn to the fact that while a constant heat input source is shown, this is only preferable, from the point of view of convenience. Heat input can vary, and if it does, this increase is merely balanced by additional throughput of sample.

Reference will now be had to FIGURE 3, which shows an alternative embodiment of the EBP apparatus employing a pneumatic control system. In the operation of the system of FIGURE 3, the fluid sample enters the tower 212 from a duct 280, through a valve 218. A pressure-limiting valve 282 is connected to the tower 212 to prevent the occurrence of unsafe pressure therein.

Vapor-is discharged from the tower 212 through a duct 284 which is connected to the gauge 254. The duct 284 is also connected through a heat exchanger 286 to a duct 288, which is also connected to the vaporizing chamber 210 through a duct 290, containing a proportioning orifice 292.

The duct 288 has a drain valve 294, and is connected to a pneumatic discharge valve system 300, which is controlled by the pressure in the duct 284.

In the operation of the system of FIGURE 3, the heaviest component of the sample stream received through the duct 280 is trapped to form the pool P. The temperature of the pool P is sensed and may be manifested as disclosed in FIGURE 2, or converted into a representative electrical signal as by a transducer 301 as shown in FIG- URE 3, which may comprise simply a thermocouple. If

the temperature is manifested by an electrical signal, thesignal may be employed to provide remote indications or utilized as a process-control data signal.

The system of FIGURE 3 functions to accumulate and maintain the pool P in a manner somewhat similar to that of FIGURE 2. The valve system 300 operates in response to the vapor pressure in the duct 284. The vapor discharge from the tower 212 and the proportioned discharge from the pool P through the duct 290 bear a preset ratio, as described with reference to FIGURE 2. The proportion of the substance discharged from the pool P to the substance discharged through the duct 284 may vary in different applications of the system.

The heat exchanger 286 cools the fluid from the duct 284 prior to discharge, and fluid from both portions of the system is discharged from the duct 288 through the lower portion of the pneumatic valve system 300 to a waste duct 302.

One of the features of the system of FIGURE 3 resides I in the precise response of the valve system 300 to pressure changes in the duct 284.

The valve system 300 incorporates a pair of pneumatic amplifiers 305 and 307, which intensify or amplify pressure signals in the duct 284 which control a pneumatic valve in the valve system 300.

The amplifier 305 comprises a diaphragm 310 mounted in a chamber 312 and controlling a valve 314 in a passage- 316 through which air is forced. The passage 316 has an orifice mounted therein to limit the passage of g11r6from a compressed-air source coupled to the passage The passage 316 also extends to the second pneumatic amplifier 307, which is similar to amplifier 305 and includes a diaphragm 320 mounted in a chamber 322, and controlling a valve 324. The valve 324 is placed in a passage 326, which -is obstructed on both sides of the valve by orifices 328 and 330, and is adapted to be connected to a source of compressed air.

The passage 326 adjacent the orifice 330 is connected to the valve, which has a diaphragm 332 mounted to control the position of a spring-mounted ball valve 334, which is mounted between the ducts 288 and 302. The diaphragm 332 is connected through an orifice 340 to a ball 342, which is urged into the orifice 340 by a spring 344. As the pressure on the diaphragm 332 is increased, it is distorted to urge the ball 342 out of the orifice 340 and thereby open the valve 334.

In the operation of the system of FIGURE 3, as the pressure in the duct 284 increases, the diaphragm 310 is distorted downwardly, thereby closing the valve 314 to restrict the flow of air through the passage 316. As a result, the pressure in the passage 316 sharply increases to distort the diaphragm 320 downwardly, constricting the pressure in the passage 326 to cause an even sharper pressure increase therein. The pressure in the passage 326 controls the. diaphragm 332 to position the valve 334. Therefore, a slight pressure change in the duct 284 is amplified to a pressure intensity to cause the valve 334 to respond very rapidly. As a result, the entire apparatus is more responsive to variations in the characteristic of the sample fluid.

Another feature of the present invention also resides 13 in the use of fractionating means, in cooperation with the preset ratio of vapor-to-liquid drawoif. The fractionating tower 212 splits the received sample into components so that only the heaviest components of the sample stream reach the pool P, the percentage of the sample reaching pool P being dictated by the vapor-to-liquid drawolf ratio.

Percentage point readings are obtained by calibrating the apparatus with a sample of known boiling curve. Thus, when the percentage point measured by the apparatus is Y", the actual percentage point will be Y": X", Where X is the calibrated offset for a particular fluid sample.

From the foregoing, it will be apparent to those skilled in the art that the present invention provides a greatly improved and satisfactory end point and initial point monitor means, fully capable of achieving the objects and advantages herein set forth. It will be apparent, however, that variations may be made in the end point and initial point monitor without departing from the novel features thereof, and, consequently, the present invention is not to be limited to the particular arrangements herein described and shown, except as defined in the appended claims.

I claim:

1. An apparatus for determining the percentage boiling point of a fluid comprising: a vaporizing chamber; means for introducing said fluid into said vaporizing cham ber to form a liquid pool including first control means enabling said liquid pool to be maintained, on the average, at a substantially constant volume; means for supplying heat to said pool; discharge means for discharging liquid and vapor from said chamber; a second control means to control the discharge of said liquid and said vapor through said discharge means in substantially fixed proportion to each other, said second control means comprising valve means in said discharge means which is openable and closable in accordance with predetercined pressure in said vaporizing chamber; and means for manifesting the temperature of said pool.

2. An apparatus for determining the percentage boiling point of a fluid comprising: a vaporizing chamber; means for introducing said fluid into said vaporizing chamber to form a liquid pool including first control means enabling said liquid pool to be maintained, on the average, at a substantially constant volume; means for supplying heat to said pool; discharge means for simultaneously removing liquid and vapor from said chamber; a second control means to control the discharge of said liquid and said vapor through said discharge means in accordance with a predetermined pressure in said chamber and in substantially fixed proportion to each other, said second control means including pressure amplifying means operative in response to said predetermined pressure in said chamber to open said discharge means and permit discharge of liquid and vapor; and means for manifesting the temperature of said pool.

3. Apparatus according to claim 1 wherein said means for introducing said fluid into said vaporizing chamber and said first control means comprises a valve connected between a source of said fluid and said vaporizing chamber, and a float positioned in said chamber to control said valve to maintain the volume of said pool substantially constant.

4. Apparatus according to claim 1 wherein saiddischarge means comprises a liquid discharge duct and a vapor discharge duct from said chamber, said vapor duct being of such size that said vapor discharged therefrom is less than 50% by volume (condensed), of the total liquid and vapor discharged through their respective ducts.

5. Apparatus according to claim 1 wherein said discharge means comprises a liquid discharge duct and a vapor discharge duct from said chamber, said vapor duct being of such size that said vapor discharged therefrom is greater than 50% by volume (condensed) of the total liquid and vapor discharged through their respective ducts.

6. Apparatus of claim 1 wherein said vaporization chamber includes a fractionating column.

7. An apparatus for determining the initial boiling point of a fluid comprising: a vaporizing chamber; means for introducing said fluid int-o said vaporizing chamber to form a liquid pool including first control means enabling said liquid pool to be maintained, on the average, at a substantially constant volume; means for supplying heat to said pool; discharge means for removing liquid and vaporfrom said chamber, said liquid being discharged in a pre-set proportion to said vapor, and in the range of 51% to by volume (condensed) to that of the total of said vapor and liquid discharged; a second control means to control the discharge of liquid and vapor through said discharge means, and second control means comprising valve means in said discharge means which is openable and closable in accordance with a predetermined pressure in said vaporizing chamber; and means for manifesting the temperature of said pool.

8. An apparatus for determining the initial boiling point of a fluid comprising: a vaporizing chamber; means for introducing said fluid into said vaporizing chamber to form a liquid pool including first controlmeans enabling said liquid pool to be maintained, on the average, at a substantially constant volume; means for supplying heat to said pool; discharge means for simultaneously removing liquid and vapor from said chamber, said liquid being discharged in a pre-set proportion to said vapor, and in the range of 51% to 100% by volume (condensed) to that of the total said vapor and liquid discharged; a second control means to control the discharge of liquid and vapor through said discharge means in accordance with a predetermined pressure in said chamber, said second control means including pressure amplifying means operative in response to said predetermined pressure in said chamber to open said discharge means and permit discharge of liquid and vapor; and means for manifesting the temperature of said pool.

9. An apparatus for determining the initial boiling point of a fluid comprising: a vaporizing chamber; means for introducing said fluid into said vaporizing chamber at a temperature below said initial boiling point, to thereby form a liquid pool including control means enabling said liquid pool to be maintained, on the average, at a substantially constant volume; an unregulated heat source for supplying heat to said pool; discharge means for removing liquid and vapor from said chamber in substantially fixed proportion to each other to maintain said pool substantially at the initial boiling point of saidfluid, said discharge means for removing liquid and vapor being controlled by valve means operable in accordance with a predetermined pressure in said vaporizing chamber; and means for manifesting the temperature of said pool.

10. An apparatus for determining the initial boiling point of a fluid comprising: cooling means adapted to be connected to receive a sample of said fluid, for cooling said sample to a temperature below the initial boiling point; a vaporizing chamber; means for introducing fluid from said cooling means to said vaporizing chamber to form a liquid pool including control means enabling said liquid pool to be maintained, on the average, at a substantially constant volume; an unregulated heat source for supplying heat to said pool; discharge means for removing liquid and vapor from said chamber in substantially fixed proportion to each other to maintain said pool substantially at the initial boiling point of said fluid, said discharge means for removing liquid and vapor being controlled by valve means operable in accordance with a predetermined pressure in said vaporizing chamber; and means for manifesting the temperature of said pool.

11. An apparatus for determining the initial boiling point of a fluidcomprising: a vaporizing chamber containing a plurality of liquid-separating members; means for introducing said fluid into said vaporizing chamber to form a liquid pool including first control means enabling said liquid pool to be maintained, on the average, at a substantially constant volume; an unregulated heat source for continuously supplying heat to said pool; discharge means for removing liquid and vapor from said chamber in substantially fixed proportion to each other; a second control means to control said discharge means including valve means responsive to pressure amplification means, said pressure amplification means being operable in accordance with a predetermined pressure in said chamber whereby to maintain said pool substantially at the initial boiling point of said fluid; and means for manifesting the temperature of said pool.

12. An apparatus for determining the initial boiling point of a fluid comprising: a vaporizing chamber; means for introducing said fluid into said vaporizing chamber to form a liquid pool including first control means enabling said liquid pool to be maintained, on the average, at a substantially constant volume; means for supplying'heat to said liquid pool in an amount suflicient to cause a predetermined pressure to develop in said chamber corresponding to the initial boiling point of the liquid in said pool; discharge means for removing liquid and vapor from said chamber in substantially fixed proportion to each other; a second control means to operate said discharge means, said second control means including valve means in sa d discharge means and being operable to discharge liquid and vapor when said predetermined pressure is attained within said chamber, and operable to prevent discharge of liquid and vapor from said chamber when said pressure is below said predetermined value, thereby to maintain said pool substantially at its initial boiling point; and means for manifesting the temperature of said pool.

13. Apparatus according to claim 12 wherein said means for introducing said fluid into said vaporizing chamber and said first control means comprises a valve connected between a source of said fluid and said vaporizing chamber, and a float poistioned in said chamber to control said valve to maintain the volume of said pool approximately constant.

14. An apparatus for determining the initial boiling point of a fluid comprising: a vaporizing chamber; means for introducing said fluid into said vaporizing chamber to form a liquid pool including first control means enabling said liquid pool to be maintained, on the average, at a substantially constant volume; means for supplying heat to said liquid pool; discharge means for simultaneously removing liquid and vapor from said chamber in substantially fixed proportion to each other, said discharge means comprising a liquid discharge duct and a vapor discharge duct from said chamber, said vapor duct being smaller in relation to said liquid duct; a second control means to control removal of liquid and vapor through said discharge means in accordance with a predetermined pressure in said chamber whereby to maintain said pool at a point close to the initial boiling point of said fluid, said second control means comprising at least one pneumatic amplifier for amplifying the intensity of the pressure in said chamber, and a pneumatic valve connected to said discharge means and controlled by said pneumatic amplifier; and means for manifesting the temperature of said pool.

15. An apparatus for determining the initial boiling point of a fluid comprising: a vaporizing chamber; means for introducing said fluid into said vaporizing chamber to form a liquid pool including first control means enabling said liquid pool to be maintained, on the average, at a substantially constant volume; means for supplying heat to said liquid pool; discharge means for simultaneously removing liquid and vapor from said chamber in substantially fixed proportion to each other, said discharge means comprising a liquid discharge duct and a vapor discharge duct from said chamber, said vapor duct being smaller in relation to said liquid duct; a second control means to control removal of liquid and vapor through said discharge means in accordance with a predetermined pressure in said chamber whereby to maintain said pool near the initial boiling point of said fluid, said second control means comprising amplifying means for amplifying the intensity of the pressure in said chamber, and valve means in said discharge means and controlled by said amplifying means; and means for manifesting the temperature of said pool.

16. An apparatus for determining the initial boiling point of a fluid comprising: a vaporizing chamber; means for introducing said fluid into said vaporizing chamber to form a liquid pool including first control means enabling said liquid pool to be maintained, on the average, at a substantially constant volume; means for supplying heat to said liquid pool in an amount suflicient to cause a predetermined pressure to develop in said chamber; discharge means for removing liquid and vapor from said chamber; a second control means to operate said discharge means, said second control means being operable to discharge liquid and vapor when said predetermined pressure is attained within said chamber, and operable to prevent discharge of liquid and vapor in substantially fixed proportion to each other from said chamber when said pressure is below said predetermined value, thereby to maintain said pool near its initial boiling point, said second control means comprising at least one pneumatic amplifier for amplifying the intensity of the pressure in said chamber, and a pneumatic valve connected to said discharge means and controlled by said pneumatic amplifier; and means for manifesting the temperature of said pool.

17. An apparatus for determining the initial boiling point of a fluid comprising: a vaporizing chamber; means for introducing said fluid into said vaporizing chamber to form a liquid pool including first control means enabling said liquid pool to be maintained, on the average, at a substantially constant volume; means for supplying heat to said liquid pool in an amount sufficient to cause a predetermined pressure to develop in said chamber; discharge means for removing liquid and vapor from said chamber; a second control means to operate said discharge means, said second control means being operable to discharge liquid and vapor when said predetermined pressure is attained within said chamber, and operable to prevent discharge of liquid and vapor from said chamber in substantially fixed proportion when said pressure is :below said predetermined value, thereby to maintain said pool at a point close to its initial boiling point, said second control means comprising at least one amplifying means for amplifying the intensity of the pressure in said chamber, and a valve means in said discharge means controlled by said amplifying means; and means for manifesting the temperature of said pool.

18. A continuous process for measuring the percentage boiling point of a fluid material stream which comprises: introducing fluid material into a vaporizing chamber, said fluid material forming a pool which is maintained, on the average, at a substantially constant volume; supplying heat to said pool and thereby vaporizing a predetermined percentage of said fluid material in said chamber; measuring the temperature of said pool; discharging liquid and vapor from said pool in response to vapor pressure developed by said boiling pool, said liquid discharge bearing a predetermined fixed ratio to the vapor discharged, said steps of introduction of fluid material and vaporization thereof, temperature measurement thereof and dis charging of liquid constituting one cycle; and repeating said cycle commencing with the introduction of fresh fluid material into said vaporizing chamber.

19. The process of claim 18 wherein the amount of liquid discharged from the pool bears a predetermined, and minor, proportional weight relationship to the amount of vapor produced.

20. The process of claim 18 wherein the amount of liquid discharged from the pool bears a predetermined,

1 7 and major, proportional weight relationship to the amount of vapor produced.

21. An apparatus for determining the end point of a fluid comprising: a vaporizing chamber; fractionating means connected to said vaporizing chamber and adapted to receive a sample of said fluid to thereby form a pool in said chamber; a control means for maintaining said pool, on the average, at a substantially constant volume; means for supplying heat to said pool; means for removing liquid from said pool and vapor from said vaporizing chamber in substantially fixed proportion to each other through a first and sec-nd conduit means respectively, discharge through said first conduit means being controlled by the vapor pressure in said conduit means; and means for manifesting the temperature of said pool.

22. The apparatus of claim 21 wherein said means for removing vapor is sufliciently large, for a given pressure, in relation to said liquid discharge means to permit at least 51% of the sample to be vaporized and less than 49% to be discharged as liquid.

23. An apparatus for determining the end point of a fluid comprising: a fractionating means; means for introducing a sample of fluid into said fractionating means; container means, interconnected with said fractionating means, for forming a pool from a portion of said fluid sample; means for heating said pool; means for manifesting the temperature of said pool; means for discharging vapors from said fractionating means; liquid discharge control means, for removing liquid from said pool in a preset proportion to vapor discharged, controlled by the vapor pressure to said discharging vapors; and control means for limiting entry of said sample into said fractionating means in accordance with the rate of discharge of liquid from said pool and the rate of discharge of vapor from said fractionating means to maintain said pool at a substantially constant volume.

24. An instrument for continuously measuring and manifesting the end point of a volatile fluid comprising: a vaporizing. chamber adapted to be connected to a source of said volatile fluid; means for controlling the entry of said fluid into said' vaporizing chamber in accordance with the volume of liquid in said chamber and the vapor discharge therefrom to maintain a substantially fixed volume of liquid in said chamber; a liquid discharge valve in said chamber; a vapor discharge valve in said chamber controlling the opening of said liquid discharge valve; means for controlling said vapor discharge valve in accordance with the vapor pressure in said chamber whereby the liquid and vapor discharged bear a substantially fixed proportion to each other; means for heating said chamber; and means for manifesting the temperature in said chamber.

25. An instrument for continuously measuring and manifesting the end point of a volatile fluid comprising: a fractionating means; a container communicating therewith; inlet means communicating with said fractionating means for entry of said volatile fluid, said container adapted to contain a portion of said volatile fluid forming a pool therein; a first control means for maintaining said pool, on the average, at a substantially constant volume; a liquid discharge means from said container; a vapor discharge means from said fractionating means controllably interconnected with said liquid discharge means so that vapor and liquid are discharged simultaneously in I said vapor discharge; and a pneumatic valve connected to said pneumatic amplifier and controlled thereby.

27. The apparatus of claim 25- wherein said vapor and liquid discharge is controlled by means of a vapor pressure actuated switch means responsive to said vapor discharge, and solenoid controlled valve means controlled in response to said switch means.

28. The apparatus of claim 25 wherein said means for removing vapor is sufliciently large, for a given pressure, in relation to said liquid discharge means to permit at least 51% of the sample to be vaporized and less than 49% to be discharged as liquid.

29. A process for continuously measuring changes in end boiling point of fluid material, which comprises: introducing a sample of said fluid material into a heated fractionating means; vaporizing a predetermined major percentage of said fluid material, containing the lower boiling components, in said heated fractionating means, said percentage being at least 51%, but less than forming a liquid pool of the remaining fluid material sample, containing the end boiling point components of said fluid material sample; maintaining said pool at a substantially constant volume; supplying heat to said pool to maintain said liquid pool at its boiling point; measuring the temperature of said pool; discharging liquid from said liquid pool in predetermined substantially fixed minor proportion to the amount of fluid material vaporized, said liquid discharge being controlled by the vapor discharge developed by said boiling pool; and introducing fresh fluid material into said fractionating means, said same major percentage fluid material being vaporized upon reaching equilibrium.

30. A continuous process for measuring the end point of a continuous stream of fluid material, which comprises: introducing a sample of said fluid material into a fractionating means sufliciently hot to cause vaporization of low boiling components; withdrawing high boiling liquid from said fractionating means to form a pool; maintaining said pool at a substantially constant volume; heating said pool to cause boiling at equilibrium; measuring the temperature of said pool; removing lower boiling components, as vaporous material, from said fractionating means; and removing high boiling liquid from said pool, the rate of removal of said vaporous material being substantially greater than, and substantially fixed with respect to the rate of liquid removed from said pool, and the vapor pressure of said vaporous material controlling the amount of liquid removed from said pool, the rate of introduction of fresh fluid material being controlled by the amount of vapor and liquid removal to thereby provide continuous measurement of boiling point of the heaviest components forming said pool.

31. A continuous process for measuring the end point of a stream of fluid material which comprises, under equilibrium conditions, the steps of: introducing said fluid material into a heated vaporizing chamber; vaporizing a predetermined major percentage of said fluid material in said heated vaporizing chamber; forming a liquid pool vof the remaining fluid material; maintaining said pool at a substantially constant volume; supplying heat to said pool to thereby indirectly heat said vaporizing chamber; discharging liquid from said pool in substantially fixed proportion to the vapor discharged, said liquid discharge being controlled by the vapor pressure developed by said boiling pool; and introducing fresh fluid material into said heated vaporizing chamber, the amount introduced varying in accordance with the end boiling point of the fresh fluid material.

32. The process of claim 31 wherein fresh fluid material is introduced having approximately the same end boiling point as the previous material whereby approximately the same proportion of fluid material is vaporized, as before, in said heated vaporizing chamber, and approximately the same proportion of fresh fluid material forms additional liquid pool, the boiling point of said ad- 19 ditional liquid being measured, and discharging said additional liquid from said pool, in proportion to the amount of vaporization of ,said fresh fluid material.

References Cited by the Examiner UNITED STATES PATENTS 1,601,320 9/1926 Peters 202-160 1,972,853 9/1934 Johnson 137-100 X 2,339,026 1/1944 Mercer -5-.. 73-36 Blair 202-160 Mercer 73-17 Spann et a1 202-160 Clay 202-160 LOUIS R. PRINCE, Primary Examiner.

JOSEPH P. STRIZAK, RICHARD C. QUEISSER,

Examiners. 

1. AN APPARATUS FOR DETERMINING THE PERCENTAGE BOILING POINT OF A FLUID COMPRISING: A VAPORIZING CHAMBER; MEANS FOR INTRODUCING SAID FLUID INTO SAID VAPORIZING CHAMBER TO FORM A LIQUID POOL INCLUDING FIRST CONTROL MEANS ENABLING SAID LIQUID POOL TO BE MAINTAINED, ON THE AVERAGE, AT A SUBSTANTIALLY CONSTANT VOLUME; MEANS FOR SUPPLYING HEAT TO SAID POOL; DISCHARGE MEANS FOR DISCHARGING LIQUID AND VAPOR FROM SAID CHAMBER; A SECOND CONTROL MEANS TO CONTROL THE DISCHARGE OF SAID LIQUID AND SAID VAPOR THROUGH SAID DISCHARGE MEANS IN SUBSTANTIALLY FIXED PROPORTION TO EACH OTHER, SAID SECOND CONTROL MEANS COMPRISING VALVE MEANS IN SAID DISCHARGE MEANS WHICH IS OPENABLE AND CLOSABLE IN ACCORDANCE WITH PREDETERMINED PRESSURE IN SAID VAPORIZING CHAMBER; AND MEANS FOR MANIFESTING THE TEMPERATURE OF SAID POOL. 